1. Field of the Invention
The invention relates to a display apparatus. More particularly, the invention relates to a display apparatus that uses micro light-emitting diodes (LEDs) as display pixels.
2. Description of Related Art
In general, a common electrode and a micro light-emitting diode (LED) of a display panel are disposed in a display region, wherein the micro LED is located in each pixel structure region and is electrically connected to the common electrode, and an image is displayed by means of a driving control between the common electrode and the micro LED. At present, a material of the electrode material which is widely chosen for the production of the micro LED may be indium tin oxide (ITO) that has a high work function of 4.5 eV to 5.3 eV and has a high light transmittance. The existing common electrode is also made of the same material; that is, ITO, and the common electrode completely covers a forward light-emitting surface of the micro LED and should have a certain thickness, so as to have good electrical conductivity. However, since wirings and devices on a driving substrate are not resistant to high temperature, a high-temperature annealing process cannot be performed to obtain a high light transmittance and good electrical conductivity when ITO is used to form the common electrode; thereby, a light-emitting efficiency of the micro LED is lowered because the common electrode with a large thickness, a low light transmittance, and poor electrical conductivity covers the forward light-emitting surface, and a display quality of the display panel is also deteriorated. In addition, compared to metallic materials, ITO has less flexibility and lower toughness, which easily increases the difficulty of manufacturing the common electrode of the display panel, and a process yield and the electrical conductivity of the display panel are thereby affected.